ARCHIVED ADVISORY - All advisories expire after 24 hours from the posting date/time.

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The Bottom Line

The avalanche danger is MODERATE in the alpine today. Dense slabs up to 3’ in depth could be triggered in steep upper elevation terrain. These slabs sit on a layer of weak snow and have the potential to pull out entire slopes.

In addition recently formed pockets of wind slab up to 1’ deep may be triggered in very steep terrain above 2,500’.

At treeline the avalanche danger is LOW. Remember that LOW does not mean NO. In particular pay attention to groups above you when traveling in mid elevation areas with avalanche terrain directly above. Human triggered avalanches from the higher elevations have the potential to run down into the mid elevations today.

Show the Complete North American Avalanche Danger Scale

North American Public Avalanche Danger Scale

Avalanche danger is determined by the likelihood, size and distribution of avalanches.

Danger Level

Travel Advice

Likelihood of Avalanches

Avalanche Size and Distribution

5 Extreme

Avoid all avalanche terrain.

Natural and human- triggered avalanches certain.

Large to very large avalanches in many areas.

4 High

Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.

Natural avalanches likely; human- triggered avalanches very likely.

Large avalanches in many areas; or very large avalanches in specific areas.

Clear skies and good visibility will make it easier to travel into the alpine today. If you find yourself venturing into steep upper elevation terrain you will need to minimize your exposure and treat all slopes above 35 degrees with suspicion. A layer of buried surface hoar, which we have been tracking, remains intact on many slopes above 2,500’. Sitting on top of this layer are 2-3’ dense slabs.

These stiff slabs have the ability to support a lot of weight, especially where they are thickest. That all changes when you get onto thinner spots of a slab. It will be possible for multiple tracks to be put down on a slope without avalanching. It is important to know that tracks do not equate to stability.

This type of slab/weak layer combo is notorious for catching people off guard days and weeks after a storm. While we have seen signs of the weak layer gaining strength, we also have no snowpack information from any terrain above 3,500’.

If you decide to get onto bigger and steeper terrain today, it will be crucial to manage yourself and your group appropriately:

Avoid trigger points, such as steep rollovers and areas where the snowpack is thin. Only expose one person at a time, utilize islands of safety, have an escape route, and communicate plans and decisions effectively.

Keep in mind that it’s a roll of the dice on all terrain over 35 degrees above 2,500'. Slabs have the potential to propagate across slopes and carry enough volume and speed to injure and bury a person.

Avalanche Problem 2

If venturing into steep upper elevation terrain expect to encounter lingering unstable pockets of wind slab, especially on North aspects. High winds from 2 days ago formed upside down slabs up to 1 foot in depth. These slabs may be encountered in starting zones and along cross loaded gullies. Staying off of snow in steep terrain (over 40 degrees) that has a hollow sound or produces shooting cracks will be the best way in managing this concern today.

Mountain Weather

Yesterday was a mild day for weather around the area. Winds were calm to light, and predominantly out of the West/Northwest. Temperatures remained in the 20s F along ridge tops and around 30 F at sea level. No new precipitation was recorded.

Today expect mainly clear skies with some valley fog as a ridge of high pressure is stationed over the area. Ridge top winds will be light out of the Nothwest at 10 mph and temperatures at 1,000’ will be close to 30 F.

The next big weather event will involve warm and wet Southerly flow. Expect above normal temperatures with snow beginning Sunday night changing over to rain by Monday up into the mid elevations.

PRECIPITATION 24-hour data (6am - 6am)

Temp Avg (F)

Snow (in)

Water (in)

Snow Depth (in)

Center Ridge (1880')

28

0

0

30

Summit Lake (1400')

25

0

0

7

Alyeska Mid (1700')

29

0

0

24.1

RIDGETOP 24-hour data (6am - 6am)

Temp Avg (F)

Wind Dir

Wind Avg (mph)

Wind Gust (mph)

Sunburst (3812')

21

WNW

7

29

Seattle Ridge(2400')

24

variable

5

16

This is a general backcountry avalanche advisory issued for Turnagain Arm with Turnagain Pass as the core advisory area (this advisory does not apply to highways, railroads, or operating ski areas).

Riding status is not associated with avalanche danger. An area will be open to motorized use in accordance to the Forest Management Plan when snow coverage is adequate to protect underlying vegetation. Backcountry hazards including avalanche hazard are always present regardless of the open status of motorized use areas.

(Updated: Mar 20, 2019 )

AREA

STATUS

WEATHER AND RIDING CONDITIONS

Glacier District

Johnson Pass:

Open

Placer River:

Closed

Closed as of 3.20.19 due to lack of snow.

Skookum Drainage:

Closed

Placer access closed as of 3.20.19 due to lack of snow.

Turnagain Pass:

Open

Twentymile:

Closed

Closed as of 3.20.19 due to lack of snow.

Seward District

Carter Lake:

Open

Lost Lake Trail:

Open

Please stay on trail to avoid resource damage through forested areas.

Primrose Trail:

Open

Please stay on trail to avoid resource damage through forested areas.

Resurrection Pass Trail:

Closed

Closed for the 2018/19 season. Next season will be open to motorized use.

Chance of Avalanches

This graphic depicts how likely you are to trigger avalanches or encounter natural avalanches while traveling on avalanche prone slopes. Unlikely means that few avalanches could be triggered in avalanche terrain and natural avalanches are not expected. The chance of triggering or observing avalanches increases as we move up the scale. Certain means that humans will be able to trigger avalanches on many slopes, and natural avalanches should be expected.

Size of Avalanches

This graphic depicts the potential size and destructive force of expected avalanches. Small avalanches are not large enough to bury humans and are relatively harmless unless they carry people over cliffs or through trees or rocks. Moving up the scale, avalanches become large enough to bury, injure, or kill people, large enough to bury or destroy vehicles and break a few trees, and large enough to destroy railway cars, buildings, or a substantial amount of forest. Historic avalanches are massive events capable of destroying villages and gouging or altering the landscape.

Chance of Avalanches

This graphic depicts how likely you are to trigger avalanches or encounter natural avalanches while traveling on avalanche prone slopes. Unlikely means that few avalanches could be triggered in avalanche terrain and natural avalanches are not expected. The chance of triggering or observing avalanches increases as we move up the scale. Certain means that humans will be able to trigger avalanches on many slopes, and natural avalanches should be expected.

Size of Avalanches

This graphic depicts the potential size and destructive force of expected avalanches. Small avalanches are not large enough to bury humans and are relatively harmless unless they carry people over cliffs or through trees or rocks. Moving up the scale, avalanches become large enough to bury, injure, or kill people, large enough to bury or destroy vehicles and break a few trees, and large enough to destroy railway cars, buildings, or a substantial amount of forest. Historic avalanches are massive events capable of destroying villages and gouging or altering the landscape.

The information in this advisory is from the U.S. Forest Service, which is solely responsible for its content. This advisory describes general avalanche conditions and local variations always occur.
This advisory provided by the Chugach National Forest, in partnership with Friends of the Chugach National Forest Avalanche Information Center.